Smoking compositions and smoking unit containing same



United States Patent Ofifice Patented Oct. 9, 1962 3,057,757 SMOKENG COMPQSITEONS AND SMOKING UNlT CGNTAINING SAME Charles G. Albert, Basking Ridge, N.J., assignor to Minerals & Chemicals Philipp Corporation, Menlo Park, Ni, a corporation of Maryland No Drawing. Filed Feb. 12, 1960. Ser. No. 8,242 7 Claims. (Cl. 131-17) The present invention relates to smoking mixtures containing tobacco mixed with a finely divided solid material and to smoking units, especially cigarettes, containing the same. The invention has for its principal object the provision of a smoking mixture of such a character that the tobacco therein burns with an appreciably reduced tar content and the tobacco smoke is characterized by a smooth, pleasant aroma and taste.

The desirability of reducing the tar content in the mainstream of tobacco smoke, that the smoke passing through the mouth end of a smoking unit, is well-recognized. Tar from tobacco smoke is believed to be injurious to health and produces discoloration of the teeth. Most attempts in the past to reduce the tar content of smoke have centered on the use of a porous filtering means integral with and forming an end of the smoking unit.

I have discovered that when a small amount of a unique amorphous form of alumina, hereafter described, is mixed directly with smoking tobacco, the quantity of tar normally produced by the tobacco and passing into the mainstream smoke is significantly reduced.

Briefly stated, tobacco compositions of the present invention comprise a uniform mixture of tobacco with a small quantity of finely divided relatively dense alumina which is produced by thermal decomposition of aluminum nitrate. When such a tobacco composition is smoked, the amount of tar is reduced from that produced by the same weight of tobacco but in the absence of the alumina. The alumina is innoxious and has no harmful effects on the smoker even if it passes into the smokers mouth.

It has been found that aluminas produced by thermal decomposition of aluminum salts do not possess, as a class, the ability to reduce the tar content of tobacco smoke. It has also been found that many forms of alumina such as, for example, bauxite (alpha-alumina trihydrate) and alumina thermally produced by the thermal activation of bauxite are ineffective for the purpose, even when used in quantities in which the alumina produced from aluminum nitrate is eminently effective. The reason for this phenomenon is not presently understood, especially since the alumina from aluminum nitrate has a relatively low BET. surface area, typically about 57 square meters per gram, Whereas some forms of alumina which are ineffectual for the purpose have much higher surface areas and would be expected to be superior sorbents for tars. This indicates that factors other than tar sorption account for the effectiveness of the alumina from aluminum nitrate in reducing the tar content of tobacco smoke.

The starting material I employ in the preparation of the alumina is aluminum nitrate or any of its hydrates. The aluminum nitrate is heated at a temperatur and for a time sufiicient to eliminate completely the nitrate, leaving a white, rather dense mass, the particles of which are amorphous when investigated by conventional X-ray diffraction procedure. Heating the nitrate at temperatures of the order of about 1400 F. for about 1 to 2 hours will sufiice to decompose the nitrate, although somewhat higher and somewhat lower ignition temperatures may be used. The ignition may be carried out in the presence of air or other oxidizing atmosphere. The alumina is ground to provide a finely divided material, i.e., a material which is substantially all finer than 325 mesh.

The tobacco I employ is conventional leaf tobacco of the type used in cigars, cigarettes or pipes. It is reasonable to expect that reconstituted tobacco or mixtures of tobacco leaf and reconstituted tobacco may be used.

In putting my invention into practice, the alumina powder obtained by grinding decomposed aluminum nitrate is uniformly mixed with shreds of tobacco in amount of about 1 to 20 percent, and more preferably about 5 to 15 percent, based on the tobacco weight. Any method of uniformly dispersing the alumina on the tobacco particles may be used. The additive may be applied by dusting the dry material on the tobacco, by spraying a dispersion of the additive in a liquid or gaseous carrier or by other means which will readily suggest themselves to those skilled in the art. Alumina which is very fine, such as 10 microns or less, will usually adhere well to the tobacco without an adhesive. However, if dc sired, an adhesive, inorganic or organic. may be employed to secure the alumina particles to the tobacco.

Preferably, the tobacco to which the solid alumina is applied is in a form suitable for direct use in the cigarette or other smoking article for which it is intended, namely, tobacco which has been aged, shredded, humected and treated with flavoring agents and such other tobacco-treating materials as may be desired.

A filter tip integral with the column of the mixture of alumina and tobacco shreds may, if desired, form the mouth end of a cigarette of my invention. The filter tip may contain fine fibers or it may contain other microporous materials as are used in a filter tip for a cigarette. The filter tip in a cigarette of the present invention will serve a plurality of important functions. It will supplement the tar reduction realized through the use of the alumina and it will prevent finely divided alumina particles from passing into the smokers mouth.

The following examples are given to illustrate more fully my invention.

Tests were conducted to demonstrate that the total quantity of tar passing into the mainstream of the smoke from a given weight of cigarette tobacco is significantly reduced by mixing the tobacco with the amorphous alumina which is produced by ignition of aluminum nitrate. Similar tests were conducted to show the behavior of other aluminas with-the same tobacco.

was placed in a muffle furnace held at 1400 F. for 2 hours and cooled. The calcined product was then ground to percent finer than 325 mesh. The product was a white powder having a B.E.T. surface area of 56.88 square meters per gram and consisting of an amorphous substantially pure form of alumina.

A blend of Turkish and domestic cigarette tobacco supplied under the trad name Bugler was used in all of the smoking experiments.

Experimental cigarettes were prepared by uniformly dry mixing 100 parts by weight of the tobacco shreds with 10 parts by weight of the alumina powder prepared from aluminum nitrate and packing about 0.99 gram of this mixture containing about 0.90 gram of tobacco into a cigarette paper wrapper. The weight of th cigarette wrapper was approximately 60 milligrams. Control cigarettes containing about 090 gram of the Bugler tobacco per cigarette were prepared. Also made up were cigarettes containing a mixture of 100 parts of Bugler tobacco and 10 parts by weight of alumina produced by calcining aluminum tartrate at 1400 F. for 2 hours. cigarettes were conditioned at 24 C. and 58 percent R.H. before smoking.

All cigarettes were mechanically smoked by the method described in detail in Industrial and Engineering Chemistry, vol. 28, No. 7, in an article entitled Nature of Cigarette Smoke-Technique of Experimental Smoking, J. A. Bradford et al., pp. 836-839 (1936).

Cigarettes were smoked individually employing a constant puff of about 2 seconds duration once each minute and with sutficient puffs to leave abutt of about 22 mm. The smoke from 5 cigarettes of a given composition was collected in a glass-wool trap packed to give 40 cm. water pressure drop at the flow rate of 1050 cc. of air per minute. The trap was shown to collect at least 95 percent of the nonvolatile components of the smoke. trap was evacuated for 20 minutes and weighed. The weight increase divided by 5 was reported as the milligrams of tar per cigarette.

The results reported in the table represent the average of three determinations, each determination representing the result of smoking 5 cigarettes of the reported composition.

These results show that the alumina produced from aluminum nitrate was highly effective in reducing the tar content of the cigarette smoke and that the alumina made from aluminum tartrate was only about one-third as effective as the alumina from aluminum nitrate. is that the alumina from aluminum nitrate had little observable effect on the burning rate of the tobacco since about the same number of puffs left about the same length of butt in the control cigarette and the cigarette prepared with alumina produced by ignition of aluminum nitrate.

The smoking tests were repeated using tobacco mixed with various quantities of other finely divided aluminas. It was found that the tar yield of cigarettes containing alpha-alumina trihydrate in the amount of percent of the tobacco weight was a 2 percent increase over the tar The mixture of alphaalumina trihydrate with tobacco in the amount of 5 percent of the tobacco weight increased the tar yield by 11 Five percent of activated bauxite, based on the tobacco weight, decreased the tar yield by only 2 percent.

1. A smoking mixture comprising tobacco having mixed therewith a small amount of alumina which is produced by thermal decomposition of aluminum nitrate.

2. A smoking mixture comprising tobacco shreds having uniformly mixed therewith a small amount of finely divided alumina which is produced by thermal decomposi- 3. A smoking mixture comprising tobacco shreds having uniformly mixed therewith from 1 to 20 percent by weight of alumina which is produced by thermal decom- 4. A cigarette comprising shreds of tobacco in columnar arrangement enclosed in a paper wrapper, said shreds being uniformly mixed with a small amount of finely divided alumina which is produced by thermal decomposi- 5. Th cigarette of claim 4 including a filter tip integral with the shreds of tobacco and forming one end 6. A cigarette comprising shreds of tobacco in columnar arrangement enclosed in a paper wrapper, said shreds being uniformly mixed with from 1 to 20 percent by weight of finely divided alumina which is produced by All 5 yield of control cigarettes.

percent. 10

I claim:

tion of aluminum nitrate.

The

position of aluminum nitrate.

tion of aluminum nitrate.

thereof.

Also shown thermal decomposition of aluminum nitrate.

7. The cigarette of claim 6 including a filter tip integral with the shreds of tobacco and forming one end thereof.

on the Total Tar Content of Cigarette SmOke Average Average Average Pressure Average Average Tars Percent Composition of Cigarette Wt. of Drop No. of Butt Per Tar Cig., During Putts Length, Cig., Reduc' gm. Smoking mm. mg. tion cm. H2O

Control Cig. (no alumina)- 0.9464 4.5 9.4 21.9 34.9 Cig. Containing 10% 1 Alumina from Ignited Aluminum Nitrate 1.0238 5.7 9.6 21.5 28.9 17.1 Cig. Containing 10% 1 Alumina from Ignited Aluminum Tartrate 1.0237 5.3 9.6 20. 9 32. 7 6.3

1 Based on weight of tobacco. 3 Ignited at 1400 F./2 hr.

References Cited in the file of this patent UNITED STATES PATENTS 1,652,119 Halvorsen et a1. Dec. 6, 1927 2,007,407 Sadtler July 9, 1935 2,839,065 Milton June 17, 1958 2,933,420 Haden Apr. 19, 1960 2,938,818 Specht May 31, 1960 2,941,906 Hadin June 21, 1960 OTHER REFERENCES Aluminum and its Production (text) by Edwards, Frary 

1. A SMOKING MIXTURE COMPRISING TOBACCO HAVING MIXED THEREWITH A SMALL AMOUNT OF ALUMINA WHICH IS PRODUCED BY THERMAL DECOMPOSITION OF ALUMINUM NITRATE. 